SU1312694A1 - Contactless velocity transducer - Google Patents

Abstract

The invention relates to electrical engineering, namely to low-power electrical machines, and can be used as a device for controlling the movement of actuators. The aim of the invention is to enhance the functionality by providing a linear velocity measurement. The contactless speed sensor contains open magnetic circuits I and 2 of the stator with excitation windings 3 and 4 and with bore windings 5 and 6. The rotor 7 is cylindrical with two helical cuts 8 and 9 on its outer surface, in the zone of which the open stator magnetic cores 1 and 2 are located . Said screw cuts are made with equal pitch and number of passes and with opposite directions of the thread, and the rotor 7 is mounted for rotation and axial movement at the same time. Each of the core windings 5 and 6 is connected via one of the rectifiers 18 and 19 to the smoothing filter 22 and 23, respectively, each of which is connected to the differential amplifier 24 and to the adder 25. The proposed non-contact speed sensor allows you to simultaneously and qualitatively judge the rotational speed and linear velocity of the rotor, which expands its functionality when controlling the movement of actuators. 2 Il. C b (L with co J: ib

Description

I

The invention relates to electrical engineering, in particular to low-power electrical machines, and can be used in software control of electric drives as a device for continuous monitoring of the movement of actuators.

The aim of the invention is to enhance the functionality by providing a linear velocity measurement.

Figure 1 - shows the proposed sensor; 2 is a circuit diagram of a sensor.

The non-contact speed sensor contains a synchronous generator with open stator magnetic cores 1 and 2, on which excitation windings 3 and A and main windings 5 and 6, ferromagnetic rotor 7 with screw cuts 8 and 9 in increments of t and Zp. The magnetic cores 1 and 2 of the stator have poles 10, II, and 12, 13, respectively, on which teeth 1 and 15 can be made with a tooth division equal to tp. Magnetic cores 1 and 2 of the stator are installed with gaps 16 and 17 relative to the ferromagnetic rotor 7. The device also contains rectifiers I8 and I9 with load resistors 20 and 21, smoothing filters 22 and 23, differential amplifier 2A and adder 25. The rotor 7 has the possibility of simultaneous axial and rotational movement with respect to the open magnetic circuits I and 2 of the stator. To increase the magnetic conductivity of the air gaps 16 and 17, it is advisable to make the profiles of screw cuts 8 and 9 quadrangular.

Contactless speed sensor operates as follows.

When powering the windings 3 and 4 of the excitation interconnected, for example, consistently (figure 2), a magnetic field arises, the lines of which penetrate simultaneously the open magnetic circuits I and 2 of the stator, air gaps 16 and 17 and the cylindrical ferromagnetic rotor 7.

With simultaneous rotation of a cylindrical ferromagnetic rotor 7 with a frequency of rotation n (r / min) and its axial movement with a linear velocity V (m / s), axial movement of the profiles of the screw threads occurs

0

69A2

8 and 9. At the same time, in the air gap under one open magnet conductor of the stator, due to the coincidence of the directions of movement of the screw thread profiles with the direction of movement of the ferromagnetic rotor itself, the angular frequency Id is determined by the sum of the angular frequencies i) u) u) u) the gap under the second open magnetic circuit of the stator due to the opposite direction of movement relative to one another, the screw thread profiles and the direction of movement of the rotor itself, the angular frequency and) "is determined by the absolute value or by the difference of the angular frequencies u) g / w - w ((the module takes into account the possibility of two cases, when ui 7/0) 2 and when). where u) i, is the angular frequency obtained only by rotating the cylindrical ferromagnetic rotor 7; si 2Tifj - angular frequency, obtained only for

e is an account of the axial movement of the cylindrical ferromagnetic rotor 7, and

f P - f Y

1 60 2 tp where tp is the pitch of the screw cuts 8 and 9. With simultaneous rotation and axial movement of the ferromagnetic rotor 7 in the directions shown, for example, by solid arrows (figure 1), the first harmonics of magnetic fluxes and in air gaps 16 and 17 respectively, under the open magnetic circuits 1 and 2, the stator pulsates in time with an amplitude φ relative to the constant component φ according to the following laws:

F, Fo + F, pS05 C (u),)

f Fo - Fp, C08 / to, - u) 2 / t + oij,

where d is the electrical shear angle

between the open magnetic wires I and 2.

In general, 2 liters, since rectifiers 18 and 19 are connected to the core windings 5 and 6, respectively.

As a result of the change of the indicated fluxes in time, the corresponding emfs are induced in the polar windings 5 and 6:

cJ4

5 Uy - W -j-Ыф (ш, -Ьса2) з1п (и)

-I- U) 2)

dF2 U - W -7- W f / Lo -ujj / sin X

0

 U) -O2 / t + oCj,

where W is the number of turns in each of the core windings 5 and 6.

By straightening with rectifiers 18 and 19, and smoothing with filters 22 and 23 at the output of the latter, provided that IH and 19 of the same name polarity EMF c. crust windings 5 and 6 averaged voltages respectively are equal to:

UscpeAM-c (to,) -27rc, (fi + f2;

among C1 / - 2 / -2 -. - where c, - const is constant, determined by the design parameters of the sensor, namely the supply voltage of the windings 3, and 4 excitations, the number of their turns and the size of the air gaps 16 and 17.

If ff, i.e.

60

on

the output of the differential amplifier 24, the constant voltage is directly proportional to the linear velocity V of the ferromagnetic rotor 7 and is equal to 5 terms Ufc)

r 4n k,

I

where k is the gain of the differential amplifier 24; k2, const. In this case, at the output of the adder 25, the constant voltage directly npo-t is proportional to the rotation frequency of the rotor 7 and is equal to

k

UcvwM Uf cpeAn b cArAN c, f where kj, const.

If f fa, then at the output of the differential amplifier 24, the output voltage is directly proportional to the frequency of rotation of the ferromagnetic rotor 7, and at the output of the adder 25 is directly proportional to the linear speed of the ferromagnetic rotor 7 when moving it in the axial direction. This is due to the fact that the second term in this case is determined by the value (fj - f).

AT

privately

..cause

zpn

b5

when tu, 0) 2 in the root winding

6 EMF is equal to zero, since there are no ripples of magnetic conductivity in the air gap 17. The EMF induced in the core winding 5 and its frequency are directly proportional to two

controlled parameters — the frequency of rotation of the ferromagnetic rotor and the linear velocity of its axial movement. At the output of the differential amplifier 24 and the adder 25, the output constant voltages are proportional to each other.

If s, 0, then in the crust windings 5 and 6, emfs of equal magnitude are induced, the amplitudes and frequencies of which are directly proportional to the linear velocity V of the ferromagnetic rotor

five

0

five

0

five

0

five

0

five

7. f.

In this case, f,: f, but since

Lj V f, then in 6 are induced

1. - O, then at the output of the differential voltage amplifier 24 is zero, and at the output of the adder 25, the voltage is directly proportional to the linear speed of the axial displacement of the ferromagnetic rotor 7.

If n2 0 i.e. f core windings 5 and equal in magnitude of the EMF, the amplitudes and frequencies of the first harmonics are directly proportional to the rotation frequency n of the ferromagnetic rotor 7. In this case, the voltage at the output of the differential amplifier 24 is zero, and at the output of the adder 25 is directly proportional to the frequency rotation n ferromagnetic rotor 7.

The proposed contactless speed sensor makes it possible to qualitatively and quantitatively judge the rotational speed and the linear velocity of the axial movement of the rotor, which indicates the expansion of its functionality. If there is only one type of movement — only rotational or only axial movement of the rotor in the coils of the core windings of the proposed sensor induces EMF, the amplitude and frequency of change of which is directly proportional to the parameter being monitored, namely the frequency of rotation or the speed of axial movement.

Claims (1)

Invention Formula A contactless speed sensor containing a synchronous generator with the first open stator magnetic circuit, on which the field winding and the core winding and a cylindrical ferromagnetic rotor with two screw cuts with equal pitch and number of runs and opposite thread directions are located. five one of which is made on the outer surface of the rotor, characterized in that, in order to extend the functionality by providing and measuring the linear speed, it is equipped with a second stator magnetometer identical to the first, two smoothing filters and rectifiers, a differential amplifier and adder, the second screw cutting rotor performed 126946 on its outer surface, the stator magnetowires are installed along the rotor axis, each of them is located in the zone of one of the screw cuts, the 5th rotor is mounted for axial movement, and each of the main windings is connected to one smoothing filter through each of the windings of which is connected to the differential amplifier and the adder. fO / sixteen NL 75 77 Editor I. Shulla Compiled by T. Kalashnikova Tehred L. Serdyukova Proofreader G. Reshetnik Order 1978/54 Circulation 661 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, Projecto st., 4 Fig /